What is snapdiff ?

Snapdiff is the Netapp mechanism to create snapshot of a volume. These snapshots are monted on a proxy for backup. This functionality can be used to backup shares in incremental. So we 'll use a normal stgpool on Spectrum Protect server, and versioning will apply.

We need additional server with TSM client installed

• (Windows) The snapdiff option is for backing up NAS/N-Series file server volumes that are CIFS attached.
• (Linux) The snapdiff option is for backing up NAS/N-Series file server volumes that are NFS attached.

https://www.ibm.com/support/knowledgecenter/SSEQVQ_8.1.7/client/c_cfg_snapmirror_supt_netapp_snapdiff.html

https://www.ibm.com/docs/en/spectrum-protect/8.1.8?topic=cspc-configuring-netapp-spectrum-protect-snapshot-difference-incremental-backups

Compatibility matrix

https://www.ibm.com/support/pages/node/154613

IMPORTANT NOTE end of support of snapdiff

https://www.ibm.com/support/pages/using-ibm-spectrum-protect-protect-netapp%C2%AE-filers-snapdiff%E2%84%A2-changing
https://mysupport.netapp.com/info/communications/ECMLP2876788.html

Following the docs for TSM 7.1.2.2 you should enter the following commands:

we've just migrated our first vFiler from 7mode 8.2.1 to cDOT 8.3.2 - and tsm snapdiff Backup works like a charm.

But you have to be careful how to setup the connection from the TSM BAclient to the cDOT Filer.

  you need TSM BackupArchive Client Version 7.1.4.x (recommended is 7.1.4.2 due to TSM bug IT12436 http://www-01.ibm.com/support/docview.wss?uid=swg1IT12436
  a NetApp cDOT Security Role on the cDOT Cluster, which is to be backuped with TSM - of course you could use the admin role - but it's a security concern.
  this example grants very wide readonly rights for the role used, but it works - of course you can tune and optimize the rights needed for the role used in your installation.
  i've not found a sample listing for the needed commands for the SnapDiff Usage of TSM in cDOT environment. 

  security login role create -role tsm-snapdiff-role -cmddirname DEFAULT -access readonly
  security login role create -role tsm-snapdiff-role -cmddirname "vserver" -access readonly
  security login role create -role tsm-snapdiff-role -cmddirname "volume snapshot" -access all

  a NetApp cDOT User on the cDOT Cluster, which is associated with the just created Security Role. In the first line you have to define a password for that user, please use a complex one and remind that password for later use on the TSM BackupArchive Client System (in this example i've used a local cDOT User, i've not yet tried a domain-user for this - if you want to do it that way, you have to setup a domain tunnel for it in the cDOT Cluster - syntax for this is described here

  security login create -username snapdiff-user -application http -role tsm-snapdiff-role -authmethod password
  security login create -username snapdiff-user -application ontapi -role tsm-snapdiff-role -authmethod password

  the just created user has to be defined on the System which is responsible for backup of the CIFS Shares of the NetApp cDOT Cluster-System vServers/SVMs.
  just log into that System (in my example its a Windows Server System) and define it in the Client Option File Registry Hive with the TSM-Tools
  define the clustered Data Ontap Management Cluster Connection:

  dsmc set netappsvm <hostname of svm sharing the volume> <fqdn of netapp cluster management server> <svm name in cDOT-cluster> -optfile=<optfile of TSM-Node used for Backup the CIFS-Shares>

  example: dsmc set netappsvm svm1 cluster1.contoso.com svm1 -optfile=svm1.opt

  after that, the login credentials defined on the cDOT system must be defined on the TSM BAclient System responsable for the Backup too

  dsmc set password -type=filer <fqdn of cluster mgmt, running the svm> <password> -optfile<optfile of the tsm-node used for the backup>
  dsmc set password -type=filer <hostname of svm owning the volume> <password> -optfile<optfile of the tsm-node used for the backup>

  example:

  dsmc set password -type=filer cluster1.contoso.com snapdiff-user password -optfile=svm1.opt		
  dsmc set password -type=filer svm1 snapdiff-user password -optfile=svm1.opt 

  finally, you can try a backup with

  net use w: \\svm1\share1 /persistent:no

  and

  dsmc i w: -snapdiff -snapdiffhttps -optfile=svm1.opt

  the result should show something like this:

  C:\Program Files\Tivoli\TSM\baclient>dsmc i w: -snapdiff -snapdiffhttps -optfile=svm1.opt
  IBM Tivoli Storage Manager
  Command Line Backup-Archive Client Interface
    Client Version 7, Release 1, Level 4.2
    Client date/time: 04/05/2016 18:50:32
  (c) Copyright by IBM Corporation and other(s) 1990, 2015. All Rights Reserved.

  Node Name: SVM1
  Session established with server TSM-SERVER: Windows
    Server Version 7, Release 1, Level 3.100
    Server date/time: 04/16/2016 18:50:32  Last access: 04/16/2016 18:46:27

  Incremental by snapshot difference of volume 'w:'

  Connected to NetApp Storage Virtual Machine
      Management Filer Host/IP Address : cluster1.contoso.com
      Filer Version Information        : NetApp Release 8.3.2: Wed Feb 24 03:29:11 UTC 2016
      Storage VM Name                  : svm1
      Storage VM Host/IP Address       : svm1
      Storage VM Volume Style          : Flex
      Login User                       : snapdiff-user
      Transport                        : HTTPS

  Performing a Full Incremental Backup of volume  \\svm1\share1'
  Creating Base Snapshot.
  Using Base Snapshot 'TSM_CONT5703ECDC6AB08_SHARE1' with timestamp 04/16/2016 16:50:36
  Directory-->                   0 \\svm1\share1\ [Sent]
  ...
  [Sent]
  ...
  Normal File-->            42,496 
  ANS2327I Creating Snapshot Differential Change Log.
  Successful incremental backup of '\\svm1\share1'

  Total number of objects inspected:       26,814
  Total number of objects backed up:       26,814
  Total number of objects updated:              0
  Total number of objects rebound:              0
  Total number of objects deleted:              0
  Total number of objects expired:              0
  Total number of objects failed:               0
  Total number of objects encrypted:            0
  Total number of subfile objects:              0
  Total number of objects grew:                 0
  Total number of retries:                      0
  Total number of bytes inspected:          11.26 GB
  Total number of bytes transferred:        11.27 GB
  Data transfer time:                       38.75 sec
  Network data transfer rate:          305,047.47 KB/sec
  Aggregate data transfer rate:          6,261.52 KB/sec
  Objects compressed by:                        0%
  Total data reduction ratio:                0,00%
  Subfile objects reduced by:                   0%
  Elapsed processing time:               00:31:27